2 month old price!

Sale 1:

Sold for 40 keys

http://www.tf2outpost.com/trade/27590929

http://backpack.tf/profiles/76561198088699490?time=1450857600 (December 23rd)

http://backpack.tf/profiles/76561198088699490?time=1451721600 (January 2nd)

http://backpack.tf/profiles/76561198088699490?time=1451721600&compare=1450857600

Sale 2:

Sold for 45 keys

http://www.tf2outpost.com/trade/27651234

http://i.imgur.com/RU37Ndg.png

Sale 3: (going to be used to price the schadenfreude)

Sold with Aces High Hermes + Sweets for Midnight Whirlwind Schadenfreude

http://www.tf2outpost.com/trade/27638163

http://i.imgur.com/Mpj1jH8.png

Sale 4:

Unable to identify sale

http://www.tf2outpost.com/trade/27162555

http://backpack.tf/profiles/76561198088401243?time=1450944000 (December 24th)

http://backpack.tf/profiles/76561198088401243?time=1451030400 (December 25th)

http://backpack.tf/profiles/76561198088401243?time=1451030400&compare=1450944000

Sale 5:

Sold for Screaming Tiger Battin' a Thousand = 39.5 (rounding to 40 keys)

http://backpack.tf/profiles/76561198085861958?time=1450857600 (December 23rd)

http://backpack.tf/profiles/76561198085861958?time=1450944000 (December 24th)

http://backpack.tf/profiles/76561198085861958?time=1450857600&compare=1450944000

Sale 6:

Sold for Death at Dusk Flipped Trilby

http://www.tf2outpost.com/trade/27565042

http://backpack.tf/profiles/76561198170178997?time=1450252800 (December 16th)

http://backpack.tf/profiles/76561198170178997?time=1450512000 (December 19th)

http://backpack.tf/profiles/76561198170178997?time=1450252800&compare=1450512000

Notes:

http://www.tf2outpost.com/trade/27650728 - B/O of 40 keys

http://www.tf2outpost.com/trade/27162555 - B/O of 40 keys

http://www.tf2outpost.com/trade/27565042 - B/O of 40 keys

http://www.tf2outpost.com/trade/27595959 - C/O of 38 keys

Conclusion:

Three valid sales at 40, 40, and 45 keys. Taking a final range of 40-45 keys.

Feel free to support/counter my suggestion!